Added properties to NavBar and NavBarBack items

Following properties are added to NavBar and NavBarBack items.

- font-color-highlighted (Color)
- font-name-highlighted (FontName)
- font-size-highlighted (Number)
- text-shadow-color-highlighted (Color)
- text-shadow-offset-highlighted (Offset)
- font-color-selected (Color)
- font-name-selected (FontName)
- font-size-selected (Number)
- text-shadow-color-selected (Color)
- text-shadow-offset-selected (Offset)
- font-color-disabled (Color)
- font-name-disabled (FontName)
- font-size-disabled (Number)
- text-shadow-color-disabled (Color)
- text-shadow-offset-disabled (Offset)